Pain on one side of the hips may be caused by improper posture, ligament strain, lumbar disc herniation, tumor and other reasons. 1. Improper posture: If you sit for a long time and have an improper posture, it is easy to damage the local myofascia and other soft tissues, which will cause pain in one side of the hips. 2. Muscle strain: If the local trauma or frequent strenuous exercise leads to muscle strain, the symptoms of pain on one side of the hips may also occur. 3. Herniated lumbar disc: If there is a herniated lumbar disc, it may cause pain on one side of the hip due to the compression of the nerve by the disc. 4. Tumor: If there is a tumor in the pelvis or bone area, due to the erosion of the tumor on the local area, you may also feel pain in the hips. It is recommended to go to the regular hospital to do the relevant examination to make sure what causes the pain, and then adopt the suitable solution according to the situation, so as to avoid delaying the condition.